Grinding machine



Oct. 9, 1934. s HAAS 1,976,125

GRINDING MACHINE Filed May 12, 1952 3 Sheets-Sheet l F. s. HAAS GRINDINGMACHINE Filed May 12, 1952 3 Sheets-Sheet 2 Oct. 9, 1934. F. s. HAAS1,976,125

GRINDING MACHINE Filed May 12, 1932 3 Sheets-Sheet 5 Patented Oct. 9,1934 UNITED STATES PATENT OFFICE Application May 12, 1932, SerialNo.610,838

9 Claims.

This invention relates to improvements in machine tools and especiallyto improvements in grinding machines.

In the operation of grinding machines, particularly center typegrinders, the grinding wheel is fed toward the center of the work atpredetermined increments to bring the work to the desired size. In thegrinding of work pieces of a length greater than the width of thegrinding Wheel either the work or the grinding wheel is axiallytraversed relative to the other to reduce the work throughout its entirelength. Upon reduction of the work to the desired size it is necessaryto retractthe grinding wheel a given amount to permit the withdrawal ofthe work from the machine. This retraction of the grinding wheel must besufficient not only to clear the work within the machine, but also toclear the stock on the work about to be introduced in the machine. Inthe past, accidents have occurred due to the operator not retracting thegrinding wheel a suficient amount to clear the extra stock on the workthat is to be removed by grinding.

It is therefore one of the principal objects of the present invention toprovide automatic means which insures the necessary retraction of thegrinding wheel to clear successive unground or rough work pieces.

Another object of the invention is the provision of improvedsemi-automatic feeding mechanism for actuating the grinding wheel andits support relative to the bed.

A further object of the invention is the provision of improved hydraulicmechanism supplementing the normal automatic feed mechanism foractuating the grinding wheel and its support relative to the bed of thegrinder together with improved means for controlling the hydraulic feedmechanism.

Other objects and advantages of the present invention should be readilyapparent by reference to the following specification considered inconjunction with the accompanying drawings,

forming a part thereof, and it is to be understood the machine shown inFigure 1 as seen particularly from line 2-2 thereon.

Figure 3 is an enlarged elevational view of the cross 'feed operatingmechanism.

Figure 4 is a fragmentary sectional view on line 4-4 of Figure 3.

Figure 5 is a sectional view taken on line 5-5 of Figure 4.

Figure 6 is an enlarged sectional detail view of the valve returningmechanisms as seen from line 6-6 on Figure 4.

Figure '7 is a diagrammatic view illustrating the hydraulic circuitsinvolved in this invention.

Throughout the several views of the drawings similar referencecharacters have been employed to denote the same or similar parts.

While the invention is illustrated in the drawings and will be'describedin connection with a center type grinder, it is to be understood that ithas equal application to any machine tool requiring a relativeseparation between the tool thereof and the work being operated upon.Accordingly, the machine comprises a bed 10 having formed on the upperend thereof guideways 11 for supporting during its movement relative tothe bed a work supporting table 12. The table 12 has mounted thereon theusual head stock 13 and tail stock 14 supporting between appropriatecenters a work piece which is to be operated upon by the grinding wheel15. Any suitable or desirable means may be employed for translating thetable relative to the bed which means are adapted to be reversed at eachend of the reciprocal stroke thereof. For effecting the reverse of thetable, the usual reverse lever 16 is employed, being pivoted at 17intermediate its ends to the forward face of the bed, as shown inFigure 1. The table 12 has adjustably secured to its face reversing dogs18 and 19 adapted to respectively engage with the upper end of the lever16 for eflecting its reverse oscillation.

The grinding wheel 15 is secured to one end of the spindle 20 journaledin suitable bearings 21 mounted in a slide or carriage 22. The carriage22 is received in guideways 23 formed in the upper surface of a bedextension 24 which projects from the rear surfaces of the bed 10.Depending interiorly of the bed extension 24, from the carriage 22, isan arm or lug 25 in which is pirmed or otherwise secured a nut 26 inthreaded engagement with a cross feed or adjusting screw 27. As shown inFigure 2, the nut 26 has formed integral therewith or secured thereto asleeve 28 forming a guard for the threaded portion of the screw 27 toprevent dirt, grit or the like from settling on said threads.

The screw 27 projects through the bed to the forward face thereof whereit is provided with a splined portion 29 received in a similarly splinedor keywayed bearing sleeve 30 of a gear 31. The gear 31 meshes with apinion 32 integral with a stud 33 journaled in a hub 34 of a ratchetgear or wheel 35. The hub 34 is keyed to the stud 33 whereby the wheel35 and stud 33 turn as a unit and the said hub 34 is journaled onanti-friction bearings 36 supported by a cover plate 37. The plate 37 issecured in any desirable manner to the forward open end of a casing orhousing 38 secured to the forward face of the bed and which housingencloses the gear 31 and pinion 32. The ratchet wheel 35 has rotatablymounted thereon, as by a pin 39, spur gear 40 meshing with internal gearteeth 41 cut on the inside periphery of the ratchet wheel 35. The gear40 meshes at a point diametrically opposite the point of mesh with thegear 41 with a spur pinion 42 integral with a micrometer or hand wheel43 loosely journaled on a reduced portion of the stud 33. Lock nuts 44on the end of the stud 33 secure the parts to one another. Themicrometer or hand wheel 43 has mounted in it a spring pressed plunger45 including the knob or handle 46 and a pin 47 adapted to enter any oneof a plurality of perforations or sockets 48 formed in the ratchet wheel35 slightly inside the ratchet teeth 49 formed around the peripherythereof.

With the spring pressed plunger 45 interengaged with one of theperforations or sockets 48 the micrometer or hand wheel 43 and ratchetwheel 35 are rotated as a unit for rotating the pinion 32 and the gear31 which rotates the screw 27 at a rate determined by the ratio betweenthe pinion 32 and gear 31, which is comparatively high. In order,however, to actuate the grinding wheel at a very slow feed, for examplea fractional thousandth part of an inch, the knob 46 is drawn outwardlyto withdraw the plunger 47 from the socket 48 whereupon it is actuated adistance between one or more of the sockets 48, which rotates the pinion42 and planetary gear 40 for thereby rotating the ratchet wheel 35 at avery slow rate of speed. From the foregoing it will be noted that thegrinding wheel and its carriage may be actuated at a comparatively slowor a fast rate of speed through the wheel 43.

In order to feed the grinding wheel toward the work, as for example ateach end of the travel of the carriage 12, the ratchet wheel 35 hasengaged therewith a pawl 50 pivotally mounted at 51 on the end of a rod52, see Figure 1. A spring 53 has one end secured to the pawl 50 and theother end to the rod 52 for at all times tending to pull the pawl 50toward the ratchet teeth 49. The rod 52 has secured to its other end apiston 54 contained within a cylinder 55 shown in elevation in Figure 1and diagrammatically in Figure 7. The cylinder 55 has extending from itsopposite ends conduits or pipes 56 and 5'7 respectively terminating in avalve sleeve 58 carried by a bracket 59 secured in any desirable mannerto the forward face of the bed 10. Enclosed within the sleeve 58 is a.spool type valve 60 abutting o' its lower end with one end'of a spring61 which is in turn butted against a closure plug or cap 62 for normallyholding the valve 60 in the elevated position as shown in Figure 7. Thevalve 60 has extending from it a stem 63 bearing at its upper end ananti-friction roller 64 adapted to engage cam faces 65 and 66 formed onthe lower end of the reversing lever 16.

Terminating at the valve sleeve 58 is one end of conduits or pipes 67,68 and 69 of which conduit 68 is the pressure line while conduits 67 and69 are branch exhaust or return lines. The branch conduit 68 terminatesin a conduit or pipe 70 into which the pump 71 discharges an hydraulicmedium such as oil which was drawn through suction pipe 72 from a. tankor "mp 73.

It is to be understood that the piston 54 moves to the right for causingthe pawl 50 to rotate the ratchet wheel 35 in a counterclockwisedirection, as seen in the drawings, for feeding the grinding wheeltoward the work. It is also to be understood that the pawl 50 must beretracted after each feeding stroke preparatory to the next infeed ofthe wheel. In order to feed the wheel toward the work at each reversalof the table 12, the reversing lever 16 is provided with the cam faces65 and 66 which are so disposed to the valve stem 63 that uponoscillation of the lever in either direction one or the other of the camfaces will engage with the roller 64 to depress the valve 60 formomentarily reversing the flow of fluid through the conduits 56 and 57for ultimately changing the direction of reciprocation of the piston 54.In order to prevent excessive pressure in the system as when the piston54 is at one end of its stroke or when the ratchet wheel 35 is heldagainst rotative movement as when the work is tothe final size, thebranch pressure conduit 68 has connected therewith a relief valve 74which discharges through a pipe 75 to the tank or sump.

In order to reverse the direction of actuatio of the ratchet wheel, asthrough the handle 46, the pawl 50 must be; free of the ratchet teeth.11! For this purpose the' cylinder '55 has projecting from its end,through which the piston rod 52 passes, a pin or bar 110 having itsouter end 111 tapered or cam shaped to ride on the adjacent face of thepawl 50 and thereby hold the pawl out of contact with the ratchet teeth.It is to be understood that the piston 54, rod 52 and pawl 50 are alwaysretracted to the same point so that when in the retracted position thebar 110 engages the pawl as above described.

The grinding wheel and its carriage are adapted to be actuated at arapid rate during a portion of the stroke as when retracting thegrinding wheel at the conclusion of the grinding operation and whenadvancing the said wheel from a point remote from the work to a pointadjacent the same. For this reason, the screw 27 has secured to itintermediate its ends a piston 76 that is enclosed in a cylinder 77closed at opposite ends as by means of cylinder heads 78 and 79. Thehead 79 is secured to an extending sleeve-like portion 80 formedintegral with the housing 38 and projecting interiorly of the bed 10.The cylinder heads 78 and 79 each carry suitable packing to prevent theescape of hydraulic pressure from the cylinder 77 around the screw 27where it through them. The heads 78 and 79 are further respectivelyformed with ports 81 and 82 respectively in communication with pipes orconduits 83 and 84, which in turn terminate adjacent the valve casing85, see Figures 4 and 5. Y

The casing 85 encloses a rotary plug type valve 86 which is adapted tobe oscillated for alternately connecting the conduits as and 84 with thepressure line 70 and exhaust line 87 into which the branch exhaust lines67 and 69 empty. The rotary plug valve 86 has its opposite sides cutaway to form ports or passages 88 and 89 shown in Figure 5 andwith'which passages the conduits 88 and 84 are alternately connected.The pressure conduit 70 terminates, as shown in Figure 4, in the valvecasing in alignment with a longitudinal port 90 formed therein, which inturn connects with a transverse port 91 formed in the casing 85 whichempties into the passage 88. The discharge conduit 87 terminates in thecasing 85 at a. point in substantial alignment with the axial center ofthe plug valve 86 where the said'valve is provided with an opening 92which terminates in a radial port 93 emptying into the passage 89.

From the foregoing it will be seen that with the plug 86 in the positionshown in Figure 7,

the hydraulic medium in conduit 70 is connected by means or" apassageway88 with the conduit 83 for actuating the piston 76 to the leftdischarging the medium ahead of it through the conduit 84, passage 89and return conduit 87. This will actuate the grinding wheel carriage 22and grinding wheel 15 to the left as seen in Figure 2 or toward theaxial center of the work.

In order to rotate or oscillate the valve 86, it is provided on itsforward end with a reduced stud portion 94 which projects through andbeyond the cover 37 of the housing 38. Secured to the stud 94 exteriorlyof the cover 37 is alatch lever 95 having the shape substantiallyillustrated in Figure 3. The lever 95 is provided with a finger piece 96and a latch or stop portion 97 at one end and a stop portion 98 on itsside opposite to the latch 97. The valve plug 86 is provided near thestud 94 with a groove 99 in which is positioned the hook end 160 of aspring 101. The hook end 100 of the spring encircling a pin 102 carriedby the plug 86, while the other end 193 of the spring 101 is similarlyhooked about a pin 19% projecting from the housing 38. The spring 191,as seen in Figures Band 6, oscillates the valve plug 86 in a clockwisedirection and maintains the latch lever 95 in contact with a stop pin105 projecting from the forward face of the cover plate 37. With thelatch lever 95 in the position shown the plug valve 86 is positioned, asshown in Figure 7, for connecting the hydraulic medium with the righthand end of the cylinder 77 and actuating the grinding wheel to the leftor toward the work. This causes, as was above described, the grindingwheel to be fed toward the work a distance determined by the head79'whereupon the pick feed of the grinding wheel is thrown in forfeeding the grinding wheel toward the work in small increments as is theusual practice at each end of the reciprocatory stroke of the work tableas above described. This feed continues until a pin 106 projecting fromthe rear of the ratchet 85 engages. with the stop portion 98 of thelatch lever 95. At this time the work should be to the desired exactsize so that successive work pieces are reduced correspondingly. In theevent, however, due to wear of the grinding wheel, the work is slightlyoversize, the spring pressed'plunger .5 is withdrawn from one of thesockets 48 and advanced in the desired direction for retracting the pin106 from the stop. This retraction of the ratchet wheel 35 does not inany wise affect the position of the grinding wheel, so that as soon asthe plunger has been moved a sufiicient distance one or more of thesockets 48, it is re- This movement of the handle 46 is continuedthrough substantially a complete revolution of the ratchet wheel oruntil the pin 106 engages with the latch lever 95 on its under surfacefor actuating it in a counter-clockwise direction, as seen in Figure 3.This movement of the latchlever 95 raises it from the stop pin 105causing the ratchet pin 106 to ride along the under surface of the saidlatch lever into en-- gagement with the latch 97. When the pin 106engages the latch 9'7 the lever is in the position indicated in dottedlines in Figure 3, thereby connecting the hydraulic medium in the line70 with the conduit or pipe 84 for actuating the piston 76 to the rightand retracting the grinding wheel from the work. As was noted above,this actuation of the latch lever 95 takes place only after asusbtantially complete revolution of the ratchet wheel in a grindingwheel retracting direction thereby insuring suificient clearance betweenthe work center and wheel for the next rough or unfinished work piece.

After the said unfinished work piece is mounted between the head andtail stocks the handle 46 is again grasped for actuating the ratchetwheel in a direction to feed the grinding wheel toward the work. As soonas this wheel is rotated in a feeding direction the pin 106 carriedthereby leaves the latch 97 of the latch lever 95 so that its spring 101may immediately rotate the valve plug 86 to connect the hydraulicpressure with the conduit or line 88 for again feeding the grindingwheel at a rapid rate toward the work. This rapid feeding of the worktakes place during the first movement of the ratchet wheel 35 in afeeding direction so that the clearance between the Work is immediatelytaken up, leaving practically only the necessary slow feeding movementof the grinding wheel as represented by the stock on the work to beremoved.

What is claimed is: c

1. In a grinding machine of the class describedthe combination of a bed,a work supporting table mounted on the bed; a grinding wheel supportmounted on the bed for movement relative thereto toward and from thework supporting table, an adjusting screw having'an ation by the springmeans except when actuated to operate the screw a irection to move thecarriage toward the work supporting table.

2. In a grinding machine of the class described the combination of abed, awork supporting table mounted on the bed, a grinding wheel supportmounted on the bed for movement relative thereto toward and from thework supporting table, an adjusting screw having an operative threadedconnection with the carriage, a hand wheel for rotating the screw, apiston secured to the screw for effecting axial movement thereof andthereby adjusting the carriage, a valve for connecting an hydraulicmedium with opposite sides of the piston, spring means for actuating thevalve in one direction,

and mechanical means carried by the hand wheel for holding the valveagainst actuation by the spring means except when actuated to operatethe screw in a direction to move the carriage toward the work supportingtable, said means comprising a pin carried by the hand wheel adapted toshift the valve against the spring means when the hand wheel is actuatedin a direction to move the carriage away from the work supporting table.

3. In a grinding machine of the class described the combination of abed, a grinding wheel carriage mounted thereon for movement relativethereto, a bracket mounted on the forward face of the bed, feed meanssupported by the bracket and including a, hand wheel, a transmissiontrain actuated by the hand wheel, an adjusting screw having one endslidably connected with the transmission train and the other end inthreaded engagement with the carriage, a cylinder car ried by thebracket, a piston within the cylinder secured to the screw, a valvecarried by the bracket for connecting an hydraulic medium with oppositesides of the piston, and co-operating means carried by the valve andhand wheel for controlling and effecting the operation of the valve inaccordance with the operation of the hand wheel.

4. In a grinding machine of the class described the combination of abed, a grinding wheel carriage mounted thereon for movement relativethereto, a bracket mounted on the forward face of the bed, feed meanssupported by the bracket and including a hand wheel, a transmissiontrain actuated by the hand wheel, an adjusting screw having one endslidably connected with the transmission train and the other end inthreaded engagement with the carriage, a cylinder carried by thebracket, a piston within the cylinder secured to the screw, a valvecar-- ried by the bracket for connecting an hydraulic medium withopposite sides of the piston, a latch lever on said valve, an abutmentcarried by the hand wheel for engaging said latch lever when operated inone direction for limiting the rotative movement of the screw andengaging said latch lever when rotated in the other direction foractuating said valve.

5. In a grinding machine of the class described the combination of abed, a grinding wheel carriage mounted thereon for movement relativethereto, a bracket mounted on the forward face of the bed, feed meanssupported by the bracket and including a hand wheel, a transmissiontrain actuated by the hand wheel, an adjusting screw having one endslidably supported by the transmission train and the other end inthreaded engagement with the carriage, a cylinder carried by thebracket, a piston within the cylinder secured to the screw, a valvecarried by the bracket for connecting an hydraulic medium with oppositesides of the piston, a latch lever on said valve, an abutment carried bythe hand wheel for engaging said latch lever when operated in onedirection for limiting the rotative movement of the screw and engagingsaid latch lever when rotated in the other direction for actuating saidvalve, and yielding means for actuating said valve in the otherdirection.

6. In a cross feed mechanism for grinding machines or the like thecombination with a bed, and a grinding wheel supported thereby, ofacross feed screw having a threaded operative connection with thegrinding wheel, a piston on the screw intermediate its'ends, a cylinderenclosing the piston, an hydraulic source of pressure, an oscillatablevalve adapted to be alternatelyreversely oscillated for alternatelyconnecting the pressure to opposite ends of the piston, means actuablethrough a given range for effecting the alternate oscillation of thevalve at one end of its range of movement, and yielding means associatedwith the valve and co-operating with the last named means to insure theoperation of the valve.

7. In a cross feed mechanism for grinding machines and the like thecombination with a bed, and a grinding wheel supported thereby formovement relative thereto, of a cross feed screw adapted to be rotatedand axially shifted for actuating the grinding wheel at slow and fastspeeds relative to the bed, means operatively connected to the screw andactuable through a given range for imparting a given movement to thegrinding wheel, a piston connected with the screw for effecting itsaxial movement, an hydraulic pressure source for actuating said piston,a valve for alternately connecting the pressure with opposite sides ofthe piston, a valve actuator associated with the valve, and meanscarried by the screw rotating means operable at one end of its range ofmovement for engagement with the valve actuator to operate same andengageable with the valve actuator when at the other end of its rangefor limiting the rotative movement to be imparted to the screw.

8. In a cross feed mechanism for grinding machines and the like thecombination with a bed, and-a grinding wheel supported thereby for Ymovement relative thereto, of a cross feed screw adapted tobe rotatedand axially shifted for actuating the grinding wheel at slow and fastspeeds relative to the bed, means operatively connected to the screw andactuable through a given range for imparting a given 'movement to thegrinding wheel, a piston connected with the screw for effecting itsaxial movement, an hydraulic pressure source for actuating said piston,a valve for alternately connecting the pres sure with opposite sides ofthe piston, a valve actuator associated with the valve, means carried bythe screw rotating means operable at one end of its range of movementfor engagement with the valve actuator to operate same and engageablewith the valve actuator when at the other end of its range for limitingthe rotative movement to be imparted to the screw, and yielding meansfor operating the valve in its other direction.

9. In a cross feed mechanism for grinding machines and the like thecombination with a bed, and a grinding wheel supported thereby formovement relative thereto, of a cross feed screw adapted to be rotatedand axially shifted for actuating the grinding wheel at slow and fastspeeds relative to the bed, means operatively connected to the screw andactuable through a given range for imparting a given movement to thegrinding wheel, a piston connected with the with the valve actuator whenat the other end of its range for limiting the rotative movement to beimparted to the screw, yielding means for operating the valve in itsother direction, and means associated with the valve actuator where-' bythe valve may be manually adjusted.

FREDERICK S. HAAS.

